Heat removal is an important factor in computer system and data center design. The number of high-performance electronics components such as high-performance processors packaged inside servers has steadily increased, thereby increasing the amount of heat generated and dissipated during ordinary operations. Due to the rapid increase of processor, server, and rack power densities, data center thermal management can become a challenge. With increasing power densities, the air flow and the corresponding power consumption can dramatically increase in a traditional air cooling system. A proper solution is needed before the high-power density thermal management requirements exceeding the limitation of air cooling.
Liquid cooling requires delivering a liquid working fluid to cooling modules such as cold plates packaged within the server. This requires delivering liquid to the servers and to the racks within which they are housed. As a result, a liquid cooling system is very different from an air cooling system. A liquid cooling system requires more components and hardware parts for distributing and transporting cooling liquid compared to delivering cooling air with an air cooling system. Therefore, a simplified design of liquid cooling system is desirable and can bring several benefits, such as increasing the reliability, improving deployment speed, reducing the cost and so on.
Several designs exist for data center liquid cooling systems. Most use two cooling loops: a primary cooling loop (also known as an external loop) and secondary cooling loop (also known as an internal loop). In most existing solutions, a Coolant Distribution Unit (CDU) is used to thermally couple the external and internal loops. Heat is transferred from the internal loop to the external loop within the CDU and the CDU external loop connects to data center facility infrastructure. The facility infrastructure can be either a chiller plant or a chiller-less plant such as a dry cooler system or cooling tower system. The CDU internal loop connects to liquid piping, and liquid distribution manifolds, and individual cooling modules.